In the following Patent Literature 1, it has been disclosed a technology that when portable telephones are connected to each other, the portable telephones divide image data for one screen into two screens. One portable telephone displays an image of the divided one screen, and the other portable telephone displays an image of the divided other screen. Further, in the Patent literature 2, it has been disclosed a technology that an external utilization screen is created based on all the option functions implementable in an image forming device connected to a server device via a network, and any image forming device is able to be operated using the external utilization screen.